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Full text of "Diseases Of The Nose Throat And Ear"

CHAPTER 67
SINUS THROMBOSIS

The transverse (sigmoid) sinus is the venous channel most frequently affected
by purulent infection, and from it the disease may spread: (1) backwards to
the confluens sinuum (torcular); (2) rarely forwards to the superior petrosal
and cavernous sinuses; or (3) downwards to the bulb and internal jugular
vein in the neck. Thrombophlebitis of a venous sinus is one of the most
common of otitic intracranial complications. It occurs in both acute and
chronic suppurations, although more frequently in the latter. The infection
usually passes through the bone to the walls of the sinus where an extra-
dural perisinus abscess may be formed. Such an extradural abscess may be
present for a considerable period before the wall of the sinus succumbs and
a clot is formed on the adjacent wall of the vessel. If the process continues
(Fig. 189) the thrombus spreads upwards and backwards as far as the entrance
of the superior petrosal sinus and forwards and downwards to the jugular
bulb. At these points the thrombosis tends to stop, but if it extends back-
wards beyond the opening of the superior petrosal there is nothing to
prevent its reaching the confluens sinuum (torcular). In the same way the
thrombus, after passing the jugular bulb, may continue until the junction
of the common facial and the internal jugular veins is reached where again
there is a natural tendency to arrest of the process. Long before this stage
has been reached the transverse (sigmoid) sinus in the region of the upper
'knee' has become occluded. An abscess forms from the breaking down
of the clot, portions of which may pass into the blood stream and set up
abscesses in distant parts of the body (pyaemia).

Especially in cases where there is an almost complete absence of mastoid
air cells, and where in consequence the sigmoid sinus lies far forward, the
infection may pass by way of the small veins which open into the sinus
without the formation of an extradural perisinus abscess. In such conditions
the thrombosis is of endophlebitic origin, and when exposed at operation
the sinus wall may show little or no change! In rare cases the veins passing
through the floor of the tympanum to the jugular bulb may carry infection
and produce primary thrombosis of the bulb (Fig. 190). Pyaemic symptoms
come on more rapidly in these cases.

SYMPTOMS. Sinus thrombosis may run its* course without symptoms, parti-
cularly where antibiotics have been used, but typically it is characterized by
the occurrence of chilly sensations or rigors in which the temperature rises
suddenly to 39-5 or 40 C, and falls again as rapidly, the fall being accom-
panied by profuse sweating (see Fig. 185, p. 358). There may be only a single
daily rigor, as a rule in the afternoon or evening, or several may occur in
a day. A high evening temperature for several days after a mastoid operation
calls for prompt exposure of the transverse sinus. The pulse rate rises with

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